Punch presses of the type in which there are provided interchangeable punch and die assemblies are widely utilized to punch sheet metal to define individual cut-outs or particular patterns of cut-outs of apertures therein, and to nibble large contoured apertures. In such machines, the tooling may be changed manually (manual tool changer) or automatically from an indexable storage unit (automatic tool changer) with the punch being rigidly coupled to the punch press ram and the cooperating die supported in a cooperating die holder aligned beneath the punch.
The changing of the punches and dies may be effected relatively quickly in numerically controlled machines.
In the past, punch presses have used a punch assembly having one punch and one mating die in alignment with the ram, and this has required changing of the punch and die assembly whenever a different diameter or aperture configuration is required, or whenever the contour in a cut out is changing. Moreover, even in the automatic tool changer magazine, there is a limited number of punch assemblies which can be satisfactorily employed, and there are space considerations with respect to the size of the magazines and the automatic elements for effecting the changing of the tooling in the operative punch station.
In Applicant's copending application Ser. No. 546,745, filed Oct. 28, 1983, there is disclosed a multitool punch assembly where the punch tool assembly coupled to the ram and the cooperating die holder in the table or bed below the ram have a plurality of cooperating punch pins and dies, thereby increasing the number of punch pins available in the machine and avoiding the necessity for changing the tooling in registry with the ram.
Although punch presses employing this assembly have proven highly advantageous, there has been a need to provide an improved drive mechanism for engaging the multitool punch assembly in the punch station to rapidly change the punch pin in use and to facilitate insertion and removal of the assembly from the ram.
It is an object of the present invention to provide a new and improved punch press having coupled to the ram a multitool punch assembly which includes a multiplicity of punch pins which can be selectively moved from an inoperative position to an operative position by a drive mechanism which is rapidly and easily movable between a position in engagement with the punch assembly to effect such movement and an inoperative position.
Another object is to provide such a punch press utilizing a new and improved indexing and drive mechanism for the multitool punch assembly.
Another object is to provide such a punch press employing control means to ensure disengagement of the indexing drive mechanism during operation of the ram and during movement of the multitool punch assembly from and into engagement with the ram.